1. Field of the Invention
This invention generally relates to a means whereby an operator controls a machine, for example, the control of an earth working back-hoe digger. The operator is typically located upon the machine and operates it through pushing or pulling numerous levers arranged before him. Each lever usually activates only one motion of the many required to perform useful work. The operator must be trained as to the functions of each lever and must concentrate upon the sequence and degree of actuation required to obtain the desired motions. Improper sequencing or over-actuation can cause accidents such as load dropping or striking objects. Efficiency and speed of operation are very dependent upon operator skill at manipulating this multiplicity of levers with split-second timing.
2. Prior Art
This control problem has been recognized in previous inventions. Askins (U.S. Pat. No. (3,642,159) utilizes one manually operated valve, linkages, and a pneumatic circuit to sequence movements on a shovel loader. Wallace (U.S. Pat. No. 3,614,273) controls the boom arms and bucket on a front-end loader through one control handle, linkages, and three valves, providing sequential operation. Fuzzell (U.S. Pat. No. 3,524,562) controls the bucket of a loader by means which electrically release a detent which is holding the control valve at a given setting. Horsch (U.S. Pat. No. 3,534,881) utilizes linkages connected to the control valve to maintain bucket position during raising and lowering. These inventions all relate to a relatively simple machine utilized to perform repetitive operations. The operator cannot interrupt the sequence at will and quickly, and he must be seated upon the equipment. Ito and Aihara (U.S. Pat. No. 3,695,377) remotely control a tractor through electrical signals sent through a control cable to operate relays and electropneumatic actuators connected to the various tractor controls.
3. Utility
The operator of farming, mining, or earth-moving machinery often finds himself in a noisy, dusty (or wet), vibrating, and generally unpleasant environment. He may not be in the best location to observe the results of his actions. He may also be in physical danger such as cave-ins when working in tunnels, at the base of cliffs, or in excavations; his machine could tumble down steep slopes or have the ground give way beneath him when working around excavations; he may be in toxic or inflammable environments; or he might accidentally sever high pressure pipes or contact high voltage lines. This invention allows the operator to move his operating controls to a location away from the equipment and operate the equipment by actuating a size-scaled version of the movably connected portions of the equipment with the actual equipment mimicking his motions. A feedback feature restricts the operator's motions when the equipment is incapable of following within certain limits. In many cases it is not desirable to remove the operator from the machine. The use of a vehicle mounted control station provides the improved control inherent with this system, thereby enhancing the efficiency of the operation.